GPU Color Constancy

Abstract

A sensor located inside a digital camera is only able to measure the light that is reflected by an object. The reflected light varies with the spectral power distribution of the illuminant. Hence, images taken with a digital camera may show a strong color cast if an incorrect white balance setting has been chosen. Such a color cast may also be due to an automatic white balance not working correctly. In contrast, colors perceived by a human observer appear to be approximately constant. Algorithms for automatic white balance try to mimic this ability and compute a color-corrected image that appears to have been taken under an illuminant with a uniform power distribution. I show how color-constancy algorithms can be implemented very efficiently on modern graphics processing units.